Quantum Mechanics

Question: The Dirac equation shows that every particle has what?

Answer: The antiparticle is the same as the particle, only with an opposite charge.

Question: That radiation and matter have properties both of particles and of waves is called what?

Answer: Louis de Broglie suggested in 1924 that matter, like radiation, had both particle and wave characteristics.

Question: Max Planck’s great discovery was that radiation energy is emitted in packets that he called what?

Answer: Quanta is derived from the same Latin word that gives us quantity.

Question: Niels Bohr used quantum mechanics to describe which element?

Answer: Niels Bohr was able to accurately describe the spectra of the hydrogen atom in 1913.

Question: The square of a particle’s wave function describes the probability of what about the particle?

Answer: Max Born proposed this accepted interpretation of the wave function.

Question: When two particles are entangled and it is observed that one has its spin up, how long does it take for the other’s spin to be down?

Answer: Yes, even faster than it would take for light to travel between them. Albert Einstein called this “spooky action at a distance.”

Question: In quantum mechanics, the angular momentum of a particle is called what?

Answer: Particles with integer spin are called bosons, and those with half spins are called fermions.

Question: Which of these is not one of the four basic forces?

Answer: The four basic forces are gravity, electromagnetism, the strong nuclear force, and the weak nuclear force.

Question: In the Heisenberg uncertainty principle, which two measurable properties of a particle cannot be observed precisely at the same time?

Answer: When a particle’s position is known precisely, its momentum is not, and vice versa.

Question: What was the first antiparticle to be discovered?

Answer: The positron (an electron but with a positive charge) was found in 1932.